Strains of lactic acid bacteria (LAB) were isolated from several different sources and evaluated in vitro for potential probiotic effects in abalones. Two isolates (Lactobacillus sp. strain a3 and Enterococcus sp. strain s6) were highly resistant to bile salt and/or gastric juice and inhibited the growth of three abalone pathogens (Listonella anguillarum, Vibrio harveyi, and V. carchariae). Each of the LAB isolates was used to supplement diet of the abalone Haliotis gigantea for a period of 3 weeks. One group of animals received Lactobacillus sp. strain a3 added to commercial dry feed, one group received Enterococcus sp. strain s6 added to the feed, and a control group received only standard commercial feed. Culturable LAB counts of gut homogenates indicate the a3 colonized in the gut of abalones. Digestive enzyme activities and the concentrations of a number of volatile short-chain fatty acids (VSCFA) were elevated in the gut of abalones receiving feed supplemented with the two LAB strains. These results indicate that dietary supplementation can enable LAB colonization or persistence in the gut of abalone species and can potentially enhance probiotic effects.
Marinobacter comprises Gram-negative, aerobic, motile, and rod-shaped bacteria within the gamma-subclass of the Proteobacteria and is known to be halophilic or halotolerant, heterotrophic neutrophile. Two strains classified as belonging to Marinobacter, named PAD-2 and SeT-1, were isolated from marine sediment. The most closely related species of PAD-2 and SeT-1 are M. alkaliphilus and M. guinea, respectively. The strain PAD-2 exhibited remarkably higher denitrification at concentrations of 0.5 to 1 M NaCl (3-6% w/w) than at other salinities (2 and 3 M NaCl, 12-18% w/w), and optimal denitrification was observed in media with 0.5 M NaCl. The effect of pH on denitrification by strain PAD-2 was also examined, and the optimum denitrification occurred at neutral pH rather than under alkaline conditions. Overall, strain PAD-2 appears to be a novel halotolerant species belonging to the genus Marinobacter that shares many characteristics, such as substrate utilization profile and optimum NaCl concentration for growth with M. alkaliphilus.
In studies of fish behavior or the ecology of schooling fish and in estimating fish biomass, information on fish position and size are required.A method was designed for determining the position of fish in three dimensions using stereo photographs taken with an under water stereo camera system. From the obtained fish positions, the distance between fish and the camera, the size, aspect and bearing angles of fish in the field of view of the camera were calculated. The absolute errors in measurement using the present method are 0.75% for length and 0.77% for distance. The method can be successfully applied to fish with any aspect within the field of view of the stereo camera system.The results suggest that in situ information on fish can be studied in detail using this technique.
The physical and gas transport properties of hyperbranched polyimide (HBPI)-silica hybrid membranes treated with carbon dioxide (CO 2 ) gas were investigated and compared with those of linear-type polyimide-silica hybrid membranes to estimate the influence of the molecular structure and hybridization on the stability of gas transport property. For all of the membranes examined, there was no marked change in the FT/IR spectrum or the UV-VIS spectrum before and after CO 2 treatment, indicating no influence on the polyimide molecular chain and the threedimensional Si-O-Si network themselves by the CO 2 treatment. In HBPI-silica hybrid membranes, it was suggested that CO 2 treatment did not cause deterioration of stability of gas transport property. The reason for this was that the restraints of the micro-Brownian motion or the densification of polyimide molecular chains and the stiffening of the three dimensional silica networks have been induced. In contrast, mild plasticization seems to have been caused in 6FDA-based linear-type polyimide-silica hybrid membranes. In addition, although CO 2 treatment decreased both the gas permeability and the selectivity of non-6FDA-based polyimide membranes, it increased the selectivity of the 6FDA-based polyimide membranes.
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